Power circuit-breaker with current transformers and data storage device

ABSTRACT

A circuit-breaker with current transformers and with an electronic tripping device having a housing contains a data storage device for characteristic values of the current transformers and the circuit-breaker. The data storage device provided with interfaces to the electronic tripping device and to the current transformers is detachably mounted on the outside of the housing of the tripping device.

FIELD OF THE INVENTION

The present invention relates to a circuit-breaker with currenttransformers and with an electronic tripping device having a housing. Inparticular, the present invention relates to a circuit-breaker forprocessing signals supplied by the current transformers, thecircuit-breaker including a data storage device for storingcharacteristic values of the circuit-breaker.

BACKGROUND INFORMATION

U.S. Pat. No. 5,331,500 describes a circuit-breaker. A data storagedevice which is described therein is an interface card which is fixedlysecured to the support of a circuit-breaker in such a way that anoperative connection with the tripping device is not established untilthe tripping device is inserted into the circuit-breaker. Signals fromthe current transformer are sent to the tripping device through linesconnecting the current transformer to the interface card. The trippingdevice thus receives information about the characteristics of thecircuit-breaker.

Due to the fact that the data storage device is a fixed component of thecircuit-breaker and the characteristic values are stored in the trippingdevice itself, this reliably achieves the result, in comparison withanother conventional method, that invariable features of thecircuit-breaker such as the type and rated current as well as thecharacteristics of the current transformers which are also permanentlyinstalled in the circuit-breaker are invariably taken into account evenwhen the electronic tripping device is replaced. However, this meansthat when a fault occurs and the electronic tripping device issubsequently tested, such faults which have occurred in the data storagedevice are not detected. Furthermore, greater caution is required whenthe current transformers of the circuit-breakers are to be replaced andtherefore the data storage device must also be adjusted or replaced.

SUMMARY OF THE INVENTION

An object of this present invention is to improve the functional testand fault finding in circuit-breakers with a data storage device of theaforementioned type.

According to the present invention, this object is achieved because thedata storage device, which is designed with interfaces to the trippingdevice and the current transformers, is detachably mounted on theoutside of the tripping device. This achieves the result that thetripping device can be removed from the circuit-breaker only togetherwith the data storage device. Therefore, if a functional test isperformed on a tripping device removed from the circuit-breaker, thedata storage device is necessarily included in the functional test. If amalfunction is found, this ensures that the troubleshooting will extendequally to the tripping device itself as well as the data storagedevice. If it proves to be necessary to replace only the trippingdevice, the data storage device can be separated from the respectivetripping device and attached to the new tripping device. Thecharacteristic values are transferred with the data storage device.

The data storage device may be arranged on the rear wall facing awayfrom the operating front of the tripping device. The interface to thetripping device and the interface to the current transformers may bearranged on opposite sides of a circuitboard of the data storage device.This permits an expedient mounting of the data storage device on thetripping device with a small overall depth.

To ensure a reliable electric connection between the tripping device andthe data storage device, the data storage device may have a separatehousing with a fastening element that serves to connect it to thetripping device.

BRIEF DESCRIPTION OF THE DRAWING

The FIGURE illustrates a side view and a sectional view of acircuit-breaker in accordance with an exemplary embodiment of thepresent invention.

DETAILED DESCRIPTION OF THE INVENTION

The FIGURE shows schematically a side view and a sectional view of alow-voltage circuit breaker with an electronic tripping device that isaccessible on the front side and a data storage device arranged on theback of the tripping device.

A circuit-breaker 1 in accordance with an exemplary embodiment of thepresent invention is shown in the FIGURE. An electronic tripping device2 is accommodated in circuit-breaker 1 so that its operating face 3 isaccessible on the front side 4 of circuit-breaker 1. A housing 5 oftripping device 2 has fastening legs 6 which are in contact withabutments 7 of circuit-breaker 1 and are connected to them by connectingmeans 10, which are indicated schematically.

Circuit-breaker 1 has conducting paths 11, which are indicatedschematically, each with a switch contact system 12. Each conductingpath is provided with a current transformer 13 whose output signalserves to control electronic tripping device 2.

A data storage device 14 is arranged on rear wall 15 which is oppositethe operating face 3 of electronic tripping device 2. Data storagedevice 14 has its own housing 16 with a fastening element 17 which isprovided for bearing contact with the lower fastening leg 6 of housing 5of tripping device 2 and is to be connected to the latter by a fasteningmeans 20, which is also indicated schematically. Interfaces 18 and 19permit a simple electric connection of the data storage device totripping device 2 and current transformers 13.

Housing 16 of data storage device 14 contains a circuitboard 21 withcomponents that serve to transmit signals supplied by currenttransformers 13 and characteristic values for the current transformersand the circuit-breaker. Circuitboard 21 is provided with components 22and 23 of plug connectors on opposite sides. Other components of theseplug connectors include a receptacle 24 and a multipoint connector 25.Component 22 works together with receptacle 24 which is arranged on rearwall 15 of housing 5 of electronic tripping device 2, while component 23is freely accessible for plugging in the multipoint connector 25 forconnection to current transformers 13. Components 22 and 24 togetherform interface 18, and components 23 and 25 form interface 19. As willbe understood by a person of ordinary skill in the art, electronictripping device 2 can be removed from circuit-breaker 1 together withdata storage device 14 after removing fastening devices 10. If anothertripping device is to be installed into circuit-breaker 1, data storagedevice 14 is first detached by removing fastening means 20 andseparating component 22 from receptacle 24 and it can be attached to thenew tripping device in the same way. Thus, the characteristic valuesspecific to current transformers 13 and the type of circuit-breaker 1are also imparted to the new tripping device.

If electronic tripping device 2 is removed from circuit-breaker 1 fortesting, the test can be performed first for the unit of the trippingdevice plus data storage device and, if necessary, it can be continuedfor tripping device 2 and data storage device 14 separately. Therefore,it is also possible to detect a defective data storage device moreeasily and replace it if necessary.

I claim:
 1. A circuit-breaker, comprising:a current transformerproviding a plurality of signals; an electronic tripping deviceprocessing the plurality of signals provided by the current transformer,the electronic tripping device including a first housing, the firsthousing having an outside portion, a rear wall and an operating face; adata storage device storing characteristic values of thecircuit-breaker, the data storage device including at least oneinterface to the electronic tripping device and to the currenttransformer, and being detachably mounted on the outside portion of thefirst housing, the first housing being arranged on the real wall of thefirst housing facing away from the operating face of the first housing.2. The circuit-breaker according to claim 4, wherein the data storagedevice is positioned its own second housing, the second housingincluding a fastening device to couple the data storage device to thetripping device.
 3. The circuit breaker according to claim 1, whereinthe electronic tripping device including the first housing is removablymounted in the circuit breaker.
 4. The circuit breaker according toclaim 1, wherein the first housing is separate from a second housing ofthe circuit breaker.